OF THE PALMS. 27 



Chili, advances on the west side of the Andes 

 to 34°, On the east side of that chain, in the 

 Pampas of Buenos Ayres and La Plata, palms 

 extend, according to Augnste de St. Hilaire, as 

 far as 34° and 35°. Such, then, are the ex- 

 treme boundaries of the palm tribe — a line 

 varying from 34° to 44° in the northern hemi- 

 sphere, and from 30° to 38° in the southern. 

 Beyond these boundaries, and from them to the 

 poles, no palm has ever yet been found living 

 and in a state of nature. It is, however, a 

 very curious fact, that although the great 

 majority of the palm family grow in plains, in 

 a mean temperature of 81° to 86°, and seldom 

 inhabit a country more elevated than 1,900 

 feet above the sea-level, there are, nevertheless, 

 within the tropics several species of palms, 

 whose natural habitats are at so great an 

 elevation on the Andes as to belong to a climate 

 corresponding with that of the colder temperate 

 or even of the arctic zones. In the " Geo- 

 graphy of Plants " it was shown that on moun- 

 tains, in whatever part of the globe situated, 

 great elevation was invariably connected wth 

 depressed temperature, so that for about every 

 2,000 feet in altitude, a change of climate, 

 temperature, and vegetable productions was 

 experienced, equivalent to about 10° of latitude; 



